It seems to be related to using the "Spawn" action. Replacing that action with a simple "Create" action from the system object fixes it.

EDIT: I think the problem has something to do with the fact that there are two instances of the RainMaker sprite. Replacing the "Every 1 tick" event(which is actually the same as using an always event) with a "For each" event looping through the RainMaker sprites also works.

1. Instead of every tick, you should use a framerate independent condition like Every X Milliseconds. This will ensure that your rain will fall at the same rate on all computers.

2. Physics can be demanding on the CPU, so you should only use it when you absolutely need it. You should have some events to fade out raindrops and destroy them over time (in case they aren't reaching the water) and also to destroy them if they are beyond the bottom of the layout (some of them are escaping the left edge of the level). By reducing the number of physics collisions you will reduce the load on the CPU.

3. You can get a more efficient spread of rain using a loop like so:

This gives a nice, rainy feel and you don't have to spam rain every tick.

4. There is a picking issue when you spawn from an object based solely on a "every tick" or "every x milliseconds" condition. The SOL doesn't know which Rainmaker you mean, so it's picking the first one in the layout, which happens to be the small one off the screen in the left corner. That one is spawning things normally, while the one in the level is making a weird stream and acting funny. If you specify that you want all rainmakers to spawn things like that then it will work fine, but you need to pick the rainmakers somehow. I added a "For each rainmaker" loop to do so, but you could pick them another way if you like. Anyway, it works fine this way, just change your event to look like that.

so last night when I posted the cap, I found everything working fine, yet now this morning, it seems to be quite glitchy, I haven't experienced anything you mentioned Deadeye, but I did notice that the breakwall blocks seems to be made of superball rubber, where last night they just sat fairly nicely where I put them, this morning they squash each other and send each other flying on startup, and I have these white skeleton blocks, that I can't place in the water, they'll be destroyed on startup if I do.I can place them above the water and they'll appear in it perfectly, but I can't place them in it in the layout. so confusing. It also seems to suffer from the odd slowdown this morning, which I don't get at all as it was never a problem before. Here's an exe of it, hopefully it'll run. Sigh, just when I thought I was making some progress lol

and after putting the computer to sleep and moving to the internet cafe next to where I work, it works just like it did last night, the physics blocks behave, and there's no slow down, I REALLY don't get it lol

thanks, I'm still tweaking things like speeds and whatnot. I'm just not quite sure what to work on at this point, maybe getting all the different kinds of enemies I want. Or perhaps the levelling and rpg elements I want. Ideally I'd like a Diablo II style levelling system and ability trees, but in castlevania style gameplay. I'm sure I'm in way over my head lol, I know I know, start small.